


Crescendo

by starry_nights88



Category: Mortal Instruments Series - Cassandra Clare
Genre: Fanfiction of Fanfiction, Hand Jobs, M/M
Language: English
Status: Completed
Published: 2013-02-11
Updated: 2013-02-11
Packaged: 2017-11-28 22:31:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,556
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/679584
Author URL: https://archiveofourown.org/users/starry_nights88/pseuds/starry_nights88
Summary: <blockquote class="userstuff">
              <p><b>Crescendo:</b> the climax of an increase in volume or intensity -- Things have been building between them for what seemed like ages, and finally, it's time to get everything out in the open.</p>
            </blockquote>





	Crescendo

**Author's Note:**

  * For [Siavahda](https://archiveofourown.org/users/Siavahda/gifts).



Originally, he wasn't sure what woke him up, or maybe he just hadn't fallen asleep yet. He had been having trouble sleeping, after all. In the end, the reason really didn't matter. He found himself outside of his room, aimlessly wandering down the corridor with no destination in mind. As if he was caught in a trance with only the vague urge to roam. At least, that was the way it appeared, and then he turned down a long-reaching hall; piano music drifting gently across the stone to him and, idly, he wondered if that was what had led him out into the Institute at such an ungodly hour.

It wasn't a piece he recognized, but then, he never claimed to know many piano pieces. He did know who was responsible for playing it, and that knowledge caused his steps to quicken. He stopped outside of the music room and stared at the partially opened door, reaching out to open it further, but he stopped himself for reasons unknown. Instead, he leaned forward and peered through the crack. He felt like such a creeper, watching him like this, but he couldn't _help it_ – he wasn't entirely sure how he was supposed to handle this growing attraction between them. He wanted to stay away, wanted to keep some distance between them, but for the life of him, he didn't know how to stay away.

He was about to turn away, just about to force himself to leave when, "You're not half as sneaky as you think you are." The mocking accusation caught him off guard – he still wasn't used to shadowhunters and their paranormally awesome senses – and, without even warring with himself, he pushed the door open and stepped into the room.

"And, if you were half as funny as you think you are, you'd be twice as funny as you are," he huffed, glaring half-heartedly at the other boy as he made his way further into the room.

"I happen to think I'm very witty," he sniffed and, for a moment, his focus was entirely on the grand piano in front of him – he pressed out note after note and, truly, the instrumental was beautiful, whatever it was. "What are you doing up and roaming the halls at this hour, Simon?"

His voice startled Simon. He was so lost in the music, he had drifted away with the alluring notes – _He's like a damned siren_ – and it took him a moment to come back to himself as the playing slowed, softened in a way, but didn't die completely. Obviously, he was expecting Simon to answer.

Simon simply snorted softly. "I could ask you the same thing," he pointed out lightly, dodging the question because he didn't think he'd be answered and, honestly, he wasn't entirely sure how to answer the question himself. He heaved a soft, aggravated sigh as he pushed a hand through his mop of curls and made his way to one of the few chairs pulled off to the side. "I don't know, Jace, I guess I've been having trouble sleeping. I mean, with everything – "

"You should watch one of those movies – what did you call them? Star Wars? "

" _Don't_ bring them into this," Simon growled, and Jace chuckled softly as he scooted to the side pointedly; his playing having stopped completely for the time being, only resuming when Simon crossed the room and took the offered seat.

"Well, they certainly put _me_ to sleep," Jace muttered under his breath, an amused smile touching his features, seeming to brighten his entire face – not that Simon was paying attention or anything. "Now, those other movies you showed me – _those_ were good," he said, looking over at Simon (and Simon didn't totally flush and look away, because he totally wasn't staring, and this was starting to get really, really ridiculous because Jace was _taken_ and that meant he was _off limits_ – _yeah, try telling that to my raging hormones_ ) with a crooked grin. "You know, the one about the midgets and that ring."

Simon blinked and frowned in confusion. "Midgets and a ri—oh, _Jaaace_!" he groaned (and he was totally ignoring the splay of incorrect notes that Jace made when Simon said his name like that – it had became a _thing_ between them, a thing that needed to stay dead and buried because Simon wouldn't be responsible for wrecking the relationship between Jace and Alec), smacking a hand to his forehead as he shook his head. "It's called Lord of the Rings, for God's sake."

"And that's why I can't remember its name. It's _so_ uncreative—," Jace pointed out, his lips curling into a slow smirk as he turned and looked at Simon again, but this time, there was less amusement in his features and more heat. "— _Simon_."

And Simon, he felt like he was being burned alive from the inside out. He swallowed thickly and looked away – he _had to_ or else he'd do something he'd end up regretting, something he _hoped_ he'd regret anyway, something he didn't think he'd regret because wanted it so badly. He _had been_ wanting to do it since he had met Jace.

"Why do you keep doing that?"

Simon frowned in confusion as he looked at Jace, shocked to see the slightest bit of hurt flicker across his features before Jace looked down at the ivory keys for a moment. He was silent, contemplating _something_ that made his face screw up with uncertainty and hesitation; two things Simon never thought he'd see on Jace's face. And then he started to play again. Simon hadn't even realized Jace had stopped.

He swallowed again, unsure and nervous, before asking, "What? What do I keep doing?" His voice wavered, wavered because he was afraid to hear the answer. He was afraid to hear the answer because he thought he knew it. He didn't _want to_ hear the answer because he didn't want to think about his response.

Jace looked at him again as the music stopped abruptly, and Simon found himself caught in Jace's intense gaze and, for a moment, Simon felt completely vulnerable and bare before Jace. He couldn't help it, he couldn't _face it_ , he turned away again and Jace let out a soft, _defeated_ sigh that was tinged with aggravation and _hurt_.

" _That_!" Jace said – no, he growled the word out and a shiver, a shameful shiver rushed down Simon's spine at Jace's rough voice. "You _always_ look away," he accused softly. "I take a step forward and you take two steps back—" His voice broke on the last word and his fingers curled into fists on top of the piano keys; a combination of random notes filling the air. " _Why_?!" He demanded, and there was something close to desperation in his voice; a desperate confusion. "I thought you _liked_ me!" He finished, almost angrily.

Silence – thick, heavy, but strangely fragile – hung between them; a silence that Simon was in no rush to break. This conversation, it was edging into territory that he wasn't ready to deal with, wasn't ready to even face.

"Unless, unless you _don't_ like me a-and…" Jace started softly, but his voice drifted off and his statement ended with a thick swallow and, really, Simon couldn't really see his face, but what he could see of Jace's profile – the other teenager looked stricken, confused, and maybe, just the tiniest bit hurt.

Simon choked on his answer – he wasn't sure what to say, how to answer. He _liked_ Jace. He liked him a lot, probably more than he should for someone he barely knew. "I, I do – " he answered softly, stopping upon remembering _why_ he had never acted on his feelings. He remembered _why_ they couldn't do this – whatever _this_ was. He felt it rise within him; a heated anger as he gritted his teeth and looked at Jace, accusation in _his_ eyes. "But what about Alec?"

Jace let out an incredulous sound as his hands flatted out and grasped the keyboard, using it to turn himself on the bench until he was facing Simon, a look of accusing indignation on his face. " _What_ does he have to do with _us_?"

"What?! What does _Alec_ have to do with us?" Simon spat out in reply, his eyes wide and shocked. He was floored, struck by disbelief. "How can you even – what does your _boyfriend_ have to do with what's going on between us?"

" _Alec is not my boyfriend_!" Jace all but shouted, his voice bouncing off the walls as he tangled his own hands in his own hair and _tugged_ at the golden locks. "Where are you even _getting_ this from?!" He snapped; clearly shaken, clearly struggling as he hissed a breath through his teeth and, when he spoke again, there was a note of pleading – a plea for understanding – in his voice. "He's my _parabatai_ , Simon, nothing more."

Jace's voice had done from outraged to pleading in the span of just a few precious moments and Simon, he was _so_ confused as he stared at Jace; dubious and not even _daring_ to hope before he exploded, throwing his hands in the air. " _Mun – dane_!" He growled, punctuating each syllable with a sharp point to his own chest. "You're going to have to be _a little more_ specific than that!" He snapped.

Jace was quiet for a long moment, panting heavily and raggedly, as he watched Simon and, for the first time, he didn't look away. "He's my partner – my partner in battle. We protect each other. He's closer than a brother to me." He paused for a moment, and Simon _swore_ he was leaning closer, but he totally wasn't reading too much into it. "I love him, Simon, but not _how I love_ you," he finished breathlessly and Simon –

 – he never got the chance to answer, to reply, to even _demand_ why this wasn't better explained to him ages ago because— _because_ Jace's lips were _firmly_ pressed against his own and after the shock cleared (and it cleared faster than soap touching pepper in water), Simon simply _melted_ into the kiss with a soft groan against the other boy's lips as his hands jumped, flew into Jace's hair and tangled in the coordinated mess.

The kiss was both everything and nothing like how Simon had imagined it to be, and he had done a lot of imagining since meeting Jace; it was slick, smooth, and edged with a little desperation –and, _God_ , the way their lips fit together, like two puzzles pieces, was just pure perfection. He wanted to drown in Jace's lips, in his kiss. Simon wanted to lose himself with Jace and never be found again. But, what he _really_ wanted to do was touch and be touched.

Simon's hands loosened from where they were desperately grasping Jace's hair just moments before, and now they were sliding down and framing Jace's face. Simon tilted his head and parted his lips encouragingly, but Jace chose that precise moment to break the kiss. For one startling moment, Simon thought he had done something wrong or pushed too far, but Jace only turned his head and pressed a kiss to the heel of Simon's hand and then he was back with a vengeance. _With_ tongue!

And for a moment—one that seemed to stretch on forever—Simon had forgotten about what it was that he wanted to do; how he wanted to touch Jace. How he wanted to touch every single inch of him until there was no part of him that Simon hadn't had the pleasure of touching, kissing, licking, or biting – and, yeah, Simon was totally back on board with that mission.

His hands moved. He just couldn't keep them still, even if he had wanted to, and he didn't. Not at all. Nope. He needed to get his hands on Jace's bare skin before he internally combusted. He touched Jace's neck, his fingers lightly pressing against the fluttering pulse – every bit as excited as his own, but Simon didn't linger.

 He _couldn't_. Not now. Not when he knew that he _could_ touch Jace. He was greedy for it, desperate for it – his hands slid down over Jace's shoulders and down his sides and then, _then_ he realized that he wasn't the only one desperate to touch; Jace's hands had started out on…

…well, Simon wasn't entirely sure where Jace's hands _had been_ , but he knew where they were now and, really, that was all that mattered as Jace's hands slithered underneath his shirt. His fingertips curling and his nails running down Simon's back, caressing his sides and Simon arched, he _moved_ into the touch as his own hands came to rest on Jace's waist.

He realized suddenly, startlingly that it wasn't enough. Simon wanted _more_ and, surely, that was all he could think about as Jace dominated the kiss, devouring him and making him shiver and shake as Jace's tongue touched and brushed against every inch of his mouth. He almost didn't want to break the kiss. He almost didn't want to pull away. But, when it came down to it, he wantedmore than Jace's mouth on his.

Simon broke the kiss, tore his mouth away from Jace's, with a heavy pant – his breaths rolling out heavily and raggedly, and Jace just watched him; a touch of color in his cheeks and a touch of confusion in his eyes. It was that moment that Simon realized that he couldn't speak, he couldn't string together two words to save his life and he almost groaned, he almost bashed his head against the piano because he wanted so bad –

He stopped. He stared at Jace for a long moment. Their breaths mixing and their lips mere centimeters apart. And then, slowly, Simon's eyes drifted downwards until it rested on the obvious bulge between Jace's legs and – he was celebrating internally because _he_ was responsible for that, thank you very much – he choked back a gasp as his eyes snapped back up, meeting Jace's heatedly intense gaze. Slowly, _slowly_ Simon's hands started to move, started to slide down Jace's waist, his hips, his _thighs_ until one hand, just one hand was pressing against Jace's erection and the greatest, most perfect of all sounds left the blond's slightly parted lips.

A _moan_ ; so soft, so honest, and so fucking good that Simon _had to_ hear more, had to hear it again. So, once more, he tried to speak, tried to form the words to ask, "C-can I—?"

Jace's golden eyes – his piercing gaze struck Simon, tore right through him. It spoke louder than Jace ever could. Simon's fingers were clumsy, uncoordinated like he was strung out on anticipation, and getting into Jace's pants was truly a challenge. In the back of his mind, Simon was thankful that Jace had changed into his pajamas and there were no buttons to be had – all Simon did, all he had to do was tug the elastic waistband down and tuck it underneath Jace's _very_ interested cock and balls.

Swallowing thickly, Simon looked down – unable _not to_ look – and he flushed deeply with the sudden and intense urge to swallow Jace's cock down; to suck it until Jace's cum was thick and heavily sliding down the back of his throat. God, oh _God_ , he wanted it inside of him! God, he didn't want to wait, he didn't think he could. In that moment, and maybe every moment after, he wanted _all_ of Jace and Simon wanted all of him _now_. The feeling, the desire was so sudden, so jarring – it was scary and slightly overwhelming.

He closed his eyes and willed his body to stop shivering, and Jace must've mistaken the action for nerves – ha, yeah _right_ , Simon was practically salivating for his cock – because his fingers were suddenly under Simon's chin, tipping his head up.

And, Jace smiled; it was small and reassuring, but his eyes were dancing with desire as he stroked Simon's jaw. "It's alright," Jace murmured softly. "You don't—"

But, oh yes, _he did_ – Simon felt the urge like he felt the need to breathe. It was automatic. Engrained in him. And, he wouldn't be satisfied until the urge was relieved. Suddenly, interrupting Jace, Simon moved. He reached for Jace's cock, wrapping his hand around it and, for a moment, he simply held Jace in his hand and relished in the warm flesh against his palm. It was, it was better than anything Simon could've dreamed of.

Breathing heavily, raggedly with his heart hammering against his chest in excitement and arousal, Simon leaned forward and caught Jace's lips – and his gasp, _oh God his gasp!_ , as Simon started to stroke him – in a heated kiss. Jace's tongue, suddenly and determinedly, invaded his mouth – licking its way inside and Simon shuddered at the sensation as Jace completely dominated the kiss, overwhelming Simon. He gave in willingly, sucking on Jace's tongue while the blond's hand pushed into Simon's hair, cradling the back of his head before Jace broke the kiss with a sharp nip to Simon's bottom lip.

He swiped his tongue along his lip, soothing the hurt as he tilted his head to the side in question as Jace stared at him, _intently_ – it was, actually, getting kinda creepy. "What?" Simon asked breathlessly, his hand slowing – off-handedly thinking, _wondering_ if he had done something wrong or if Jace had changed his mind.

Jace rolled his hips, pushing his cock into Simon's fist as he shook his head slightly before leaning forward to chastely brush his lips against Simon's. "I want to touch you too," he murmured softly as his other hand – the one _not_ tangled in Simon's hair – brushed down Simon's back before sliding around to the front and, and –

— _oh, fuck yes_! – Jace rubbed the heel of his hand between Simon's legs, against his erection – his dick, his cock and Simon was fucking sure he had died and gone to Heaven, but he was fairly sure he could still feel his pulse throbbing through his body, or maybe that was just his dick.

"But, I've only been with girls before now…" Jace continued softly as the rubbing stopped – and why was the rubbing stopping, who said he could do that?  –  and his hand slipped into Simon's boxers and Jace's _fucking fingers_ were brushing against _Simon's cock_!

Though the lust induced haze, Simon could detect a hint of vulnerability in Jace's voice, but it was laced with determination – soft and _fierce_ , and really, Simon could respect that – as he continued speaking; "I don't know – "

"It's okay," Simon replied quickly, softly, and in what he hoped was a reassuring voice instead of desperate – because, he thought he sounded a little desperate. "I can, I can show you a-and – _mmm_ , that's a good start," he said breathlessly, his voice breaking with a moan as Jace's hand wrapped around Simon's erection. "A _really_ good start," Simon added, his voice shaking, as he rolled his hips into Jace's hand and he would've been content to keep doing that – keep fucking Jace's hand, but apparently, that wasn't what Jace had in mind.

"Simon," Jace murmured throatily as his fingers curled in Simon's hair, tugging at it slightly to get his attention. " _Show me_."

Simon let out a breathless moan, almost a freaking whine, but he nodded in understanding as he let go of Jace's cock – he hadn't  to notice yet, he seemed really interested in what he was doing to Simon at the moment. With a trembling hand – not from nerves, but from excitement, anticipation, and _fucking arousal_ – he reached into his own boxers, nudging them out of the way so Jace can see, and laid his hand on top of Jace's.

"Watch me," Simon softly stated, almost commanded, as his fingers intertwined with Jace's and, _slowly_ , he started to guide Jace's hand over his erection. He set the pace, the pressure, and he even showed Jace a few tricks – a few things Simon enjoyed; "A-and your thumb," he murmured breathlessly, his voice soft and shuddering as his own thumb rubbed at the leaking head of his erection. "Just, just like – _fuck, Jace_! – just like _that_!" Simon groaned as he tipped his head back, staring up at the high, vaulted ceiling without really seeing it. He bucked his hips, rolling his cock into their joined hands as Jace mimicked – _expertly_ mimicked what Simon had just shown him.

"Like that?"

Jace's voice was light, teasing, brimming with a confidence that hadn't been present until that very moment – he twisted his hand, and his fingers pressed against the thick vein running along the underside of Simon's cock. He played Simon as well as he played the piano sitting next to them; skillfully and filled with a certain tenderness that took Simon's breath away – well, that and the fact that Jace was jacking him off.

His eyes fluttered, nearly closed, and his entire body jerked in pleasure before Simon's hand fell away – really, he didn't think Jace needed the help or guidance anymore. His hand fell to the bench, grasping its edge with a white-knuckled grip as Jace's hand continued to move over his cock. Simon's entire body shook, it trembled, and his entire body felt like it was _on fire_ and, already, he could feel the sweet swell of release building in his abdomen. He breathed raggedly; trying to calm himself, trying to center himself because he didn't want it all to end. He didn't want to cum and lose this wonderful feeling, this addictive closeness.

But, " _Simon_ ," Jace husked softly against his ear, and then his lips were on Simon's skin, burning a trail of steaming kisses along the column of his throat. Simon tried, he fucking _tried_ to hold back the whimpers, the sighs, but they came anyway as Jace's kisses grew more aggressive until they were _bites_ and Simon was choking on his gasps of pleasure. He tipped his head back as Jace bit and sucked at his skin, and his hand continued to move, move perfectly and just how Simon liked it and –

 – _holy shit, no!!_   Simon came with a soft, surprised groan of Jace's name. His entire body tensing, and then relaxing as his seed spurted out of the tip of his penis, coating his stomach and Jace 's hand with the white viscous fluid. He looked down at himself – at himself wrapped in Jace's hand, his spunk staining Jace's hand and, again, Simon groaned softly in embarrassment and shame. "I didn't mean to do that," he murmured softly, tortured.

A thick, heavy silence followed his statement. One that bordered on awkward, and an awkward silence was the last thing that Simon needed at this point. But then Jace – he _laughed_ , and Simon frowned almost automatically, looking up at the blond.

 "I don't see what's so – " Simon started, but Jace smoothly interrupted him with a chaste, but heatedly sweet kiss.

" _Hush_ ," Jace breathed against his lips, his hand falling away from Simon's spent cock. "Don't apologize for that. This isn't a race."

Simon snorted softly in reply, turning away to hide his blossoming smile as the awkwardness simply melted away. "Good thing too," he replied softly, teasingly, a smirk touching the upturned curve of his mouth as he turned back to Jace. "If it had been a race, I would've beaten you," Simon said, eyes twinkling as his gaze shifted and he looked down, between them, once again. This time, however, he looked at Jace instead of himself, relieved and renewed to see that the other boy was still hard and sluggishly leaking precum.

"Maybe you should do something about that?" Jace suggested lowly, raggedly, fucking _heatedly_ and, in that moment, Simon swore Jace's voice sounded like pure sex.

Naturally, there was only one thing Simon could do; it was pure, simple, and startlingly easy. He loosened his grip on the piano bench, flexing his fingers before reaching for Jace, for his neglected erection. Jace let out a soft sigh as Simon's fingers wrapped around him and, slowly, Simon started to stroke him. Hungrily, his eyes scanned Jace's face, his expression, drinking in and relishing any and every physical embodiment of the pleasure Simon was providing him.

It felt like he was drunk – drunk on the power he held over Jace in that moment. _He_ was the one doing this to Jace. _He_ was the one getting Jace off. He had his hands on Jace's body; working him, playing him like he played his guitar. And, the sounds he made – _Simon_ was responsible for those; the soft moans, sighs, and broken groans. It was dizzying, electrifying. It _really_ felt like he was drunk. He reveled in the fact that he was doing this to Jace, that Jace was this far gone _because of_ Simon. It was certainly an ego-trip if nothing else, but then, it was so much more than that. It was something so much deeper, so much more perfect and completely – it was something Simon couldn't even fathom.

Suddenly, Simon stopped. He paused, and pulled his hand away from Jace's body. Grinning slightly as Jace's eyes brightened, becoming more focused and more confused. "Why'd you – " Jace started, but his voice died in his throat as Simon lifted his hand, grinning mischievously all the while, to his mouth and tongued a line from the heel of his palm to his fingertips. His hand returned to Jace, wrapping around him and stroking so much more smoothly, so much more perfectly and Jace tipped his head back, groaning Simon's name softly.

" _Yes_ ," Simon hissed, his voice barely above a whisper – and, he was really getting into this. He was _really_ enjoying touching Jace, making him feel this way. He leaned forward, leaned into Jace as Simon's hand pressed against Jace's thigh for leverage. Simon touched his lips to the base of Jace's throat, sucking kisses across the flesh; gaining confidence as Jace groaned in pleasure and bucked into the spit slickened ring Simon's fingers made. His tongue traced a path, a trail that was soon followed by his teeth raking across Jace's skin, before Simon was biting down and leaving behind marks. All the while, Jace's lips were pressed against his ear – panting and murmuring Simon's name, over and over again while Jace's body shuddered and shook.

And then suddenly, almost viciously, Jace's lips were crushing against his own in a bruising kiss, and Jace was sucking down Simon's surprised gasp. Simon drank it all in, sucked it all down, relished in it as Jace's teeth sank into his bottom lip with a ragged groan and, suddenly, Simon's fingers were wet with cum. That's when Simon realized, with a start, that Jace had gotten off – that _he_ had gotten Jace off, and Simon couldn't smile at that moment, but he eagerly returned the kiss. He opened his mouth to Jace's demanding tongue, and licked right back into Jace's mouth. He shivered, Jace shook, and they clung to each other –

 – even after the kiss was broken and they were panting heavily, catching their breaths, with their foreheads pressed together. They smiled at each other; Simon's cheeks were flushed and Jace's lips were curved in a smirk. They didn't say anything, but for the moment, there _was_ nothing to say. Because everything that needed to be said, could be said tomorrow.

**Author's Note:**

> This was _heavily_ inspired by Sia's fanfiction [City of Shadows](http://archiveofourown.org/works/585318/chapters/1051650).
> 
> It was, and still is, a scene that _won't_ leave me alone and, usually, when that happens I have to write them out. This time, that resulted in fanfiction based on my friend's fanfiction.
> 
> City of Shadows doesn't need to be read to understand this (I think I pretty much stripped everything that would cause that from my piece), but if you're any kind of Jimon fan, you seriously need to read Sia's fanfiction.


End file.
